There are many kinds of insulin that are prescribed for our FD cats. Some perform much better than others and each has its idiosyncrasies. Sometimes we will have a choice when it comes to which insulin is prescribed by our vets; sometimes we won't. Whatever insulin, all insulin types have been proven to work with TR.
It is advised to start TR / Insulin when you are available to monitor your cats BG frequently by performing frequent testing and/or curves for the first few days until you know how your cat processes their insulin.
One of the important premises TR is built on is maintaining overlap between doses – meaning that the remnants of the prior shot are still working to keep the BG from rising very high, while the next shot approaches onset (when the insulin starts to work). Different insulin types have different durations -experienced members on forum will help guide you through the process of understanding the nuances of the insulin you are using to get maximum results.
Insulin should be stored in the fridge at all times, in a protected spot on a less-used shelf, in a sturdy, padded container where it will not get knocked over. Do not store insulin on the door of your fridge to avoid excess jostling. Practicing TR we handle our insulin more often than when dosing twice a day. Handling your insulin gently and with care will prolong potency considerably.
Dr. Hodgkins' Tight Regulation protocol was developed for use with bovine based PZI insulin but it has been proven over time that many insulin types work very well with TR.
Please scroll down this page for explanations about the different insulin types which will help you chose the right insulin for your circumstances. Insulin types described below are:
PZI (Protamine Zinc Insulin)
Lantus (aka Glargine)
Levemir (aka Detemir)
Caninsulin (aka Vetsulin)
NPH (Humulin N)
Fast Acting Insulin Types (NR/Novolin)
In the TR College of Knowledge (COK), review the Info sticky for your individual country to determine which insulin is available or may be imported.
Standard recommendation is to do a number of BG testing curves (either full curves or mini curves) when first starting TR, changing insulin, or when increasing/decreasing doses. The dosing scales provided are a starting point and you should expect adjustments to be needed, increasing the dose amounts as you learn how your cat processes insulin and what it's insulin needs are. These adjustments will happen quickly (in two to three shot cycles) in order to get your cat's BG to normal range (below 8.3/150) as soon as possible. The goal at the start of TR is to get your cat's BG down below 13.8/250 within the first week, and ideally into "double digits" (BG of 2.8 to 3.8/50-70) if possible. BG below 13.8/250 is considered to be below "renal threshold" where the chance of ketones being produced is minimized, which in turn protects from DKA (Diabetic KetoAcidosis). Please see the Detox Process sticky for further information about starting TR safely to prevent clinical hypo.
If it is available in your country - Dr. Hodgkins' preference for TR is 100% bovine based PZI which is only one amino acid away from a cat's own insulin, and is a very gentle, predictable insulin for felines. Bovine based PZI is available in both compounded and manufactured types, and in a variety of strengths from U40 to U100 depending on the source.
The most common PZI types in the US are BCP (bovine), Stokes (bovine). Unfortunately VPA/US is no longer compounding bovine based PZI due to costs. In Canada, Summit PZI (bovine) is available; all are compounded versions of bovine based PZI insulin which is not quite as stable as manufactured PZI. Manufactured 100% bovine PZI is also available in the UK under the name Hypurin Bovine Protamine Zinc and can be imported to other countries (see your country's Info sticky). ProZinc is manufactured protamine zinc recombinant human insulin which is salmon based.
Compounded Bovine PZI from BCP, Stokes and Summit
The challenges with compounded insulin means that there can be variances from batch to batch and if at all possible, for a variety of reasons including sterility issues, manufactured insulin is recommended where available (manufactured bovine based PZI insulin is not available in the USA). BCP and Stokes are still compounding PZI and have advised they have a well-stocked supply of bovine pancreatic materials to continue compounding indefinitely. VPA has stopped compounding bovine based PZI due to difficulties sourcing the bovine pancreatic materials. Summit PZI is only available in Canada; however the company has had difficulties sourcing pancreatic materials in the past, running out of supply without notice.
Compounded PZI typically comes in 10ml vials, in U40 or U100 strengths and must be prescribed by a vet. Depending on how much insulin your cat needs and how the vial is handled, a vial can last from one to three months or much longer.
When ordering BCP for the first time, there is a free 5ml vial of U100 that is sent to your vet. Most vets, if asked, will pass this free vial along to you for your cat. BCP also sends a number of free "promotional" items to your vet for placing their first order. The coupon for the free vial is on their website - just click on the BCP link above, print out the coupon and give it to your vet.
Hypurin Bovine Protamine Zinc Insulin
Hypurin is the only manufactured, U100 bovine based PZI type left in the world and is made by CP Pharma/Wockhardt in the UK. We recommend Hypurin as the replacement to Insuvet which has been discontinued (Insuvet was the "vet" version of Hypurin and can be switched out dose for dose). Depending on where you live, you may be able to import Hypurin to your country either directly for personal use, or through a government run fee-for-permit or special access program which requires vet participation and can significantly increase costs. The distributor for Hypurin in the UK is Weldrick's - to order Hypurin internationallyvisit MastersGlobal or from North America call the toll-free number 1-800-969-1152. A three month supply of Hypurin can be easily imported to Canada for personal use (see the Canadian Info sticky for details including customs documentation information); to import to the US involves obtaining a special fee-based FDA permit. If you are interested in importing Hypurin for your cat, contact the Health branch of your countrys government offices to verify specific requirements. Taxes and duty normally apply when importing insulin for companion animals.
Hypurin is a very interesting bovine based PZI as it provides longer lasting durations, a slower curve, and significant overlap due to its extended depot properties (ECID). It is available in U100 strength only, and is only one amino acid away from a cat's own insulin. The manufacturer recommends that when giving a shot, leaving the needle in place for 5 seconds before removing the syringe. Hypurin is not without its own idiosyncracies, particularly when it comes to overlap. Members on forum can help you understand the nuances of this insulin type.
ProZinc (protamine zinc recombinant human insulin) was launched in the US in November 2009. It is the only FDA approved insulin for exclusive use in felines. ProZinc is the replacement insulin for Idexxs PZI vet. ProZinc is U40 in strength. As at the time of this update, it is reported that ProZinc will be available in Canada; it must be purchased through a vet and will likely be very expensive.
Most vets in the US will likely prescribe ProZinc as their choice of replacement for Idexx PZI Vet (now discontinued). ProZinc is a recombinant human insulin which is salmon based, and its markers are 4 amino acids away from a cats own insulin. ProZinc is formulated exactly like its predecessor PZI Vet, with the exception of salmon based RHdna replacing the 90% bovine/10% porcine pancreatic materials. ProZinc has a PH of 7.1 to 7.4which is slightly higher than a cat's normal PH.
Pricing of ProZinc will vary depending on your vets mark-up. If you live in the US, Pet Meds will price match as long as you provide a competitors website when ordering ProZinc by phone. Please see the US Info sticky for links to price match for considerable cost savings.
Starting PZI Treatment
If your cat has been on another form of PZI and you are switching brands, depending on your cat`s BG, we recommend to allow approximately 10 to 12 hours to pass between doses of the two different PZI insulin types. If your cat has been on long lasting insulin such as Lantus or Levemir, allow approximately 18 to 24 hours to pass before starting PZI. For medium acting insulin types such as Vetsulin/Caninsulin and/or NPH, a minimum of 10 to 12 hours to pass before starting PZI is recommended. For further assistance when switching insulin types, please post on the Talking TR forum.
U100 strength PZI must be used with U100 syringes. When using U40 strength PZI, you have the option to use either U40 syringes, available only from your vet, or to use U100 syringes (3/10cc with half unit markings). Purchasing U40 syringes from your vet is very expensive (prices range from $25 to $40 per box of 100-U40 syringes). A box containing 100 syringes with half unit marks for use with U100 insulin can be purchased for as little as $12.50 at Wal-Mart. The second advantage to using U100 syringes with U40 PZI is the ability to more accurately measure doses in as little as 0.2u increments. This is very handy should your cat be sensitive to insulin and need only slight increases/decreases to dosage. While U40 syringes with half unit marks are available, they are very difficult to source.
Please be aware that there are several sizes of U100 needles, each holds different amounts of fluid - 3/10cc/ml, 1/2cc/ml and 1cc/ml. The 3/10cc and the 1/2cc both have draw lines on the barrel that equal one unit, while each of the draw lines on the 1cc syringe equals two units. It is important NOT to buy 1cc syringes, as the 2u draw lines can make it very easy to overdose! We strongly recommend buying ONLY U100 3/10cc syringes for 30u of insulin or less - with half unit markings!
When using U40 insulin with U100 syringes, you MUST use a conversion chart to factor for the difference in volume between U100 and U40 strengths. You can find the conversion charthere. Briefly, U100 insulin is 100% insulin U40 insulin is 40% insulin with 60% suspension added (typically saline). In order to make up for the difference in the percentage of insulin between the two strengths when using U100 syringes, the U40 insulin must be multiplied by 2.5 for example, if you need 1.0u of U40 insulin and you are using a U40 syringe, you simply draw to the 1.0u line on the syringe. However, when using U40 insulin with U100 syringes, to get the same 1.0u of insulin, you need to draw the insulin to the 2.5 unit line on the U100 syringe. It is the same amount of insulin, just a different volume depending on which syringe is used. This is a little baffling at the beginning of TR but, as long as you are using the conversion chart, make sure to put old U40 syringes far out of reach, and remember that there are two steps to loading the syringe identifying the amount of the dose, then making sure you convert for the DRAW on the syringe, it is safe to use U100 syringes.
More so than other insulin types, PZI is very fragile. Practicing TR we typically handle our insulin more often than twice a day. It is very important to keep movement of the insulin to a minimum. Vials should be turned end over end very gently, only three to four times before drawing your dose. The vial should not be rolled between warm hands, or shaken, regardless of what the manufacturers instructions state. An interesting discovery made on forum is that should a vial begin to lose potency, PZI insulin types seem to revitalize if left to "rest quietly" in the fridge for a week or two.
When preparing to draw a dose of PZI, pull the plunger back on the syringe a unit or two more than the desired dose before inserting the syringe into the vial. With the vial upright, stick the syringe into the vial and slowly express the air in the syringe into the vial to create a vacuum. Once the syringe is empty of air, then gently turn the vial upside down and draw insulin into the syringe, just past the desired dose. With the vial still upside down, slowly expel the extra insulin back into the vial until the correct dose is in the syringe, then remove the syringe from the vial.
PZI is long lasting insulin generally claimed to remain in the system for approximately 12 hours per shot - years of on-forum testing have shown that PZI tends to leave the system hours earlier for most cats. When first starting TR, onset usually occurs between +2 and +3 hours after shot; nadir is typically from +4 to +6 hours after shot, and by +8 hours after shot, the insulin begins to leave the system. These time lines are the norm and are likely to change as your cat begins to heal: ECID - every cat is different.
PZI is insulin that can be dosed as early as +6 hours after the last shot when the rise in BG has been confirmed. In fact, at the start of TR, we recommend you try as much as you can to dose every +6 hours with a BG confirmed to be rising over 150/8.3, to get the overlap working for you as soon as possible. If schedules do not permit consistent +6 dosing to start, working with a +8 dosing schedule is more than acceptable.
With PZI we are able to react much quicker to less than satisfactory results. If after two or three shots to scale, you are not seeing BG in the ideal range at nadir (below 8.3/150), doses can be increased. Experienced members will help you adjust your scale to get your cat into optimal normal range numbers as quickly as possible.
Recommended Starting Scale for PZI (after 12- 24 Hour Detox)
US(mg/dl) Metric(mmol/L) Dose
Lantus/Glargine is human insulin that comes in U100 strength and requires the use of U100 syringes. It is sold in either 10ml vials, or 3ml cartridges or comes inside a pen forum (cartridges and pens usually come in 5 packs) that are designed for use with injection pens that are purchased separately. We recommend purchasing Lantus cartridges, but do not recommend buying the injection pens because they only allow for half or full unit dosing - it is impossible to measure part unit doses using a pen. Lantus cartridges look very much like "mini" vials, with a rubber stopper at the top. Purchasing cartridges will be more expensive at the outset (about $25-$30 more than a 10ml vial of Lantus) but there is much less waste compared to purchasing 10ml vials. The manufacturers of Lantus state it expires approximately 28 days after opening, so it's likely that even a 3ml vial would not be empty by the time Lantus loses its potency. We recommend storing Lantus in the fridge. Depending on how it has been handled, we have found that Lantus can remain potent for months, well past 28 days.
Lantus is clear, just like water. Should you ever see any crystals in the vial or cartridge, the Lantus has been damaged and should be discarded. If bubbles appear in Lantus, it will start to lose potency. Unlike when filling a syringe with PZI, it is recommended not to draw air into the syringe to express into the vial when measuring a Lantus dose, nor to back the insulin out of the syringe while it is still in the vial - in an effort to avoid creating air bubbles. Draw more than your required Lantus dose into the syringe by at least a half to full unit, remove the syringe from the vial and express the extra insulin onto a paper towel or tissue to avoid creating bubbles.
Lantus is available at any drug store as it is commonly used in humans. In some countries, like Canada for example, Lantus is available over the counter and does not require a prescription. If you are purchasing Lantus through your vet, you may wish to check pricing with your local pharmacy first in order to save yourself the extra cost of vet mark-up. Prices differ greatly for example, premier drug stores charge $30 to $40 dollars more, where well-known stores such as Wal-Mart and Costco charge a lot less for Lantus.
When giving insulin shots, particularly with Lantus, you want to slowly push the plunger of the syringe in completely and with the syringe still inserted under the skin, slowly count to 10 before removing the needle from the injection site. You may have to hold your cat gently while you wait. Remove the syringe and very gently apply pressure for several seconds. DO NOT RUB THE AREA to avoid damage to the Lantus molecules.
Lantus is long lasting insulin, remaining in the system for 12 hours or more. It typically drops the BG slowly, has an extended nadir, and begins to slowly leave the system after approximately 8 to 10 hours. These are the norm, every cat is different. It is very important to maintain overlap on Lantus meaning that the remnants of the prior shot are still working to keep the BG as close to normal range as possible, while the next shot is coming to onset. Typically +10 dosing is recommended for Lantus to maintain overlap at the start of TR.
Lantus is insulin that should not as a rule be dosed any sooner than +10 hours after the last shot, and only to a rising BG over 150/8.3. It is imperative that your cat is curved on the first three or four shots when starting out, or when making even very minor dosing changes. The first curve starts with the test before shot, continues with testing every two hours afterwards to determine onset, nadir (peak insulin activity) and when the insulin starts to leave the system. Typically onset for Lantus is 3-4 hours after shot, nadir occurs at +6 to +8 hours after shot with the insulin beginning to leave the system from +8 to +10 hours after shot. The timing for tests on the second curve is dependent on the first curves results.
When using Lantus, rather than starting with a static dose every 12 hours as is typically prescribed, the use of a three rung sliding scale is recommended, with dosing at approximately every 10 hours as determined by the cats progress. When compared to PZI, a tighter dosing scale is used with Lantus and we find that the scale becomes almost "static" over time (one to two dosing rungs), with only very small adjustments made to doses to deal with later or earlier dosing. Eventually the Lantus scale is reduced to two rungs, and then possibly to one rung as the cat becomes better regulated.
Unfortunately there is a big challenge to using Lantus. It is released over time and does not result in the instant gratification that is seen with most of the other insulin types. In humans, Lantus crystals are still present in the system 24 to 48 hours after dose. In cats, due to their much faster metabolisms, Lantus lasts approximately half that time.
It takes approximately two, if not three shots of Lantus before you know if the dose is doing what it is supposed to do, such as reaching ideal numbers at nadir. If ideal BG is not reached after two to three doses, increases will typically be made by either "fat" increases or a maximum increase of 0.25u increments depending on your testing results. In some cases where it is very clear doses are not working, increasing by 0.5u may be called for. Experienced members on forum can help you determine the correct strategy for your cat.
For members in the US, a special offer for Lantus is available applicable on the first vial purchased.
Using Lantus requires PATIENCE.
Recommended Starting Scale for Lantus (after 24 Hour Detox)
US ( mg/dl) Metric (mmol/L) Dose
150 - 250.......8.3 - 13.9............0.25u
251 - 400......14.0 - 22.0............0.5u
400 +...........22.2 +.................0.75u
Levemir is another new to the market, synthetic human insulin which is now being used on felines although most vets do not know about it. It works very similarly to Lantus with a long lasting, gentle absorption action. It is a depot insulin with a gentle and predictable or "peak less" curve. Unlike Lantus, Levemir is PH neutral; as well, depending on the cat, it can if necessary be dosed as early as every 8 hours to start to fill the depot quickly. Experienced members on forum can assist to determine if earlier dosing will work better for your cat. Typically onset for Levemir is 3-4 hours after shot, nadir occurs at +6 to +8 hours after shot with the insulin beginning to leave the system from +8 to +10 hours after shot.We are seeing on forum, cats that have not been well regulated on Lantus or other insulin types can become much better regulated after being switched to Levemir when the right scale is worked towards aggressively. There is some feedback that cats switched from Lantus to Levemir appear to "feel" better after making the switch. For members in the US, on the Levemir site there is a $50.00 "off" coupon applicable for the US only on the first vial purchased.
Recommended Starting Scale for Levemir (after 24 Hour Detox)>
US ( mg/dl) Metric (mmol/L) Dose
150 - 250.......8.3 - 13.9............0.25u
251 - 400......14.0 - 22.0............0.5u
400 +...........22.2 +.................0.75u
Caninsulin (aka Vetsulin)
Caninsulin is insulin which was created for dogs, hence the name Canin-sul-in. Caninsulin is the first insulin vets will prescribe for diabetic cats in Europe. Cats in Canada are quite often prescribed Caninsulin at diagnosis. In the US, Caninsulin is knows as Vetsulin. In past years, typically a cat's curve on this insulin was very similar to that of an NPH curve. Due to speculation about changes in composition, cats generally seem to be responding much better to Caninsulin than before, particularly when first diagnosed. For some cats, Caninsulin can drop the BG very fast, nadir is relatively short lived, and it leaves the system very quickly resulting in what we can refer to as a "roller coaster" as far as BG curves are concerned. For others, the curve is far more gentle - ECID. While many cats do achieve successful diabetic remission using it, Caninsulin may not be the best insulin for your cat. For this reason, if available in your country, it is recommended if available, to initially purchase the 2.5ml vial of Caninsulin from your vet (rather than a 10ml vial) because if Caninsulin does not provide the desired results within two to three weeks, there will be less waste and expense. Experienced members on forum will be able to guide you if it appears over time that your cat might prefer another insulin choice.
Caninsulin/Vetsulin is a porcine insulin zinc suspension (PIZ rather than PZI)), at least 3-4 amino acids away from a cat's own insulin. It is U40 in strength and is generally prescribed with U40 syringes only. It is available in both 10ml and 2.5ml vials depending on country. It is uniformly cloudy or milky. It should be stored in the fridge in an upright position to avoid crystals forming around the stopper. Caninsulin is intermediate acting insulin, meaning that onset usually occurs between +1 and +2 hours after dose; nadir is approximately +4 to +6 hours after dose and it usually has left the system by +8 hours after dose. Caninsulin typically does not last +12 hours in cats, especially at the start of TR. These approximate times are the norm, every cat is different.
In order to be able to more accurately measure doses, it may be recommended to switch to U100 syringes with half unit marks. A conversion is required to use U40 insulin with U100 syringes. Please visit the Conversion Chart sticky for more information, and seek assistance on forum if you aren't "sure" when developing a dosing scale to use U40 insulin with U100 syringes.
Recommended Starting Scale for Caninsulin (after 24 Hour Detox)
US(mg/dl) Metric(mmol/L) Dose
NPH (Humulin N) Insulin
NPH (Neutral Protamine Hagedorn) is human recombinant insulin, which comes in U100 strength and must be used with U100 syringes. It is very similar to natural canine insulin and is commonly used for dogs. NPH should appear cloudy in the vial. It is one of the cheapest insulin types on the market (approximately $35.00 per vial depending where you live), and can be left at room temperature for up to 28 days, although refrigeration will increase length of potency. It is stable insulin in that it is not quite as sensitive to knocks and drops as the others. It should not be used after the expiration date. There should be no clumps or white particles in the suspension. If clumps or spots appear, turn the vial end over end a number of times to see if the clumps or spots dissipate. If they do not, the insulin is damaged and should not be used.
It is approximately 3 to 4 amino acids away from a cat’s own insulin. It is highly recommended to do 1-hour curves when using NPH, starting at +1 after shot until the insulin starts to leave the system. Onset for NPH occurs between +1 and +2 hours after shot, nadir is approximately +2 to +4 hours after shot, and it leaves the system usually by +6 hours after shot. These are the norm, every cat is different. NPH is insulin that if needed, can be consistently dosed earlier than +6 hours after shot to a rising BG in special circumstances only. Experienced members will help you decide what approach to take with NPH. Even more so than Caninsulin, NPH typically drops the BG fast, has a very short nadir and leaves the system very quickly. It is not abnormal to see drops from a BG in the 400s(20.0s) to the 40s (2.0s) and back up to the 400s (20.0s) within a six hour period.
NPH is not the best choice for cats. That said, for some cats it has worked well. NPH is an acceptable "in a pinch" insulin for times when for example, youve dropped and shattered your vet-prescribed insulin vial on the floor, the vet clinic is closed for a couple of days, and the drug store is still open. NPH can be used in dire situations where ketones are high and the need to get the BG down quickly is required. Please ask for assistance on forum should you need to switch to NPH in an "urgent" situation.
Recommended Starting Scale for NPH (after 24 Hour Detox)
US(mg/dl) Metric(mmol/L) Dose
Fast Acting Insulin Types
There are a number of fast acting insulin types that may be of assistance for very hard to control cats, or when ketones have developed and/or a cat has developed DKA. One of the fast acting insulin types is known as "NR", the proper name is Novo Rapide in Canada and Europe. It is known as Novolog in the US. Because TR is an aggressive protocol, most cats on TR do not require fast acting insulin and therefore, we do not provide standard dosing recommendations for this insulin type. If you find yourself in the situation where fast acting insulin is required, please post on Talking TR asking for case-by-case assistance from a member experienced with fast acting insulin, and, you should ALWAYS confer with your vet on how they are best used, what to watch out for and whether or not fast acting insulin is even appropriate for your cat's specific situation.
If you have any questions about any of the information provided in the Insulin and Starting Scales sticky, please post your questions on the Talking TR forum.
© Diabetic Cat Care - Updated March 2014